1. Field of the Invention
The present invention relates to a trailer hitch and particularly to a trailer hitch that has a retaining latch bolt to reduce shaking to prevent pilferage and stabilize the latch bolt without sliding.
2. Description of the Prior Art
U.S. Pat. No. 6,409,203 discloses a trailer hitch which mainly includes a latch bolt 11, a retaining element 12 and a locking head 13 (referring to FIG. 1). The retaining element 12 is coupled with an elastic element 14 and held in a first coupling member 21. The retaining element 12 has a screw hole 121 corresponding to a first bolt opening 211 of the first coupling member 21. It also has a second coupling member 22 to be coupled with the first coupling member 21. The second coupling member 22 has a second bolt opening 221 corresponding to the first bolt opening 211 to allow the latch bolt 11 to run through. Incorporating with the locking head 13 a locking operation can be performed. To avoid the latch bolt 11 from sliding and shaking while the trailer is moving on a bumpy road, an external thread section 111 is formed on the latch bolt 11 to screw with the screw hole 121 of the retaining element 12. The coupling tolerance of the latch bolt 11 can be adjusted. The elastic element 14 also provides a thrusting force to reduce sliding and shaking of the latch bolt 11. Although the aforesaid structure can thwart pilferage and prevent the latch bolt 11 from sliding and shaking, it still has drawbacks in practice, notably:
1. The retaining element 12 is held in the first coupling member 21 which has no anchoring means, hence alignment of the first bolt opening 211 and the screw hole 121 is difficult. Coupling of the latch bolt 11 could be hindered.
2. When the latch bolt 11 runs through sequentially the second bolt opening 221, first bolt opening 211 and screw hole 121, the retaining element 12 is prone to be pushed and moved, thus coupling is more difficult.
3. The external thread section 111 of the latch bolt 11 is screwed with the screw hole 121 of the retaining element 12, hence the front section 112 of the latch bolt 11 cannot be made too large. A bushing 3 has to be provided on the front section 112 to reduce the tolerance of the latch bolt 11 and the first and second bolt openings 211 and 221 (a larger tolerance will result in greater sliding and shaking).
4. To facilitate screwing adjustment of the external thread section 111 and the screw hole 121, a grip section has to be provided on the bolt head 110 to be clamped by a tool. After locking, the bolt head 110 can be easily broken to damage the lock by ill-intentioned people.